---

yaml --- r: 61650 b: refs/heads/master c: 7ed5cb2 h: refs/heads/master v: v3
git-mirror · Jul 19, 2007 · e39f559 · e39f559
1 parent f0d3498
commit e39f559
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Showing 2 changed files with 8 additions and 4 deletions.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: e3aded3cc289113c7bc729ef4cb75e56d9aa71be
+refs/heads/master: 7ed5cb2b73d0c4165c0504c95454fade0c0bf3d9
diff --git a/trunk/mm/hugetlb.c b/trunk/mm/hugetlb.c
@@ -104,15 +104,19 @@ static int alloc_fresh_huge_page(void)
 {
 	static int prev_nid;
 	struct page *page;
-	static DEFINE_SPINLOCK(nid_lock);
 	int nid;
 
-	spin_lock(&nid_lock);
+	/*
+	 * Copy static prev_nid to local nid, work on that, then copy it
+	 * back to prev_nid afterwards: otherwise there's a window in which
+	 * a racer might pass invalid nid MAX_NUMNODES to alloc_pages_node.
+	 * But we don't need to use a spin_lock here: it really doesn't
+	 * matter if occasionally a racer chooses the same nid as we do.
+	 */
 	nid = next_node(prev_nid, node_online_map);
 	if (nid == MAX_NUMNODES)
 		nid = first_node(node_online_map);
 	prev_nid = nid;
-	spin_unlock(&nid_lock);
 
 	page = alloc_pages_node(nid, htlb_alloc_mask|__GFP_COMP|__GFP_NOWARN,
 					HUGETLB_PAGE_ORDER);